1. Field of Invention
The present invention relates to a radar system technology, and particularly to an apparatus and a method for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map.
2. Description of the Related Art
In a radar system, filtering and restraining clutter and electronic countermeasures are two subjects. In a scanning space of radar, no matter desired target (e.g. planes) or undesired target (e.g. mountain, cloud, rain etc.) reflects EM wave of radar system and generates echo signal received by an antenna of the radar system. So-called clutter is the echo signal generated by the undesired object. The interference of clutter affects probability for detecting desired target for a radar system, and results the false alarm rate of erroneous target increasing. To establish a clutter map is a method for effectively filtering and restraining the clutter. The said clutter map is a clutter data recorder in scanning area of a radar system. That is, recording intensity of clutter generated by an object in a scanning area of a radar system to establish a clutter intensity space map in the scanning area. The clutter map is used to generate a detection threshold.
Conventionally, the area established by clutter map is all scanning area of a radar system or partial stationary area. In fact, a valid area of a clutter map is a range generating clutter affecting a radar system for detecting target, so the clutter map only establishes the area where a clutter exits. Furthermore, what is called interference map records an area with an object generating clutter in a scanning area of a radar system. In other words, the interference map is a spatial map recording a distribution of a plurality of clutter blocks in the scanning of the radar system. It is using a clutter map memory with limited capacitance effectively and flexibly by establishing clutter map only for an area indicated a clutter block according to an interference map. In addition, for the area indicated clutter block according to the interference map, the radar selects different searching mode, like moving target indication (MTI), to filter clutter.